Wireless Local Area Networks (WLAN) is a data transmission system. It uses radio frequency (RF) technology to replace the old twisted-pair copper wire formed by the local area network, making the wireless local area network can use a simple access architecture allows users through it, to achieve the purpose of information transmission. The development and application of WLAN technology has deeply changed people's communication way and working way, and brought people unprecedented convenience. With the wide application of intelligent terminals, the demand for data network traffic is increasing day by day.
WLAN development is inseparable from the development and application of its standards, including IEEE802.11 series is the main standard, there are 802.11, 802.11b/g/a, 802.11n, 802.11ac. In addition to 802.11 and 802.11b other standards are used Orthogonal Frequency Division Multiplexing, OFDM technology as the physical layer of the core technology.